21436899025 has 12 divisors (see below), whose sum is σ = 26844943644. Its totient is φ = 16979720000.

The previous prime is 21436899019. The next prime is 21436899041. The reversal of 21436899025 is 52099863412.

It can be written as a sum of positive squares in 6 ways, for example, as 1536718401 + 19900180624 = 39201^2 + 141068^2 .

It is not a de Polignac number, because 21436899025 - 2¹⁷ = 21436767953 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21436899025.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4242406 + ... + 4247455.

It is an arithmetic number, because the mean of its divisors is an integer number (2237078637).

Almost surely, 2^21436899025 is an apocalyptic number.

21436899025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21436899025 is a deficient number, since it is larger than the sum of its proper divisors (5408044619).

21436899025 is a wasteful number, since it uses less digits than its factorization.

21436899025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8489972 (or 8489967 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 49.

The spelling of 21436899025 in words is "twenty-one billion, four hundred thirty-six million, eight hundred ninety-nine thousand, twenty-five".